Health-related quality of life assessment is rapidly becoming an indispensable tool for evaluating outcome in medicine. By addressing the quality of patient health after treatment, these assessments greatly enhance the study of treatment effectiveness, they are used in the study of cost and outcome relationships (i.e., cost-effectiveness analysis), and they offer a universal standard in health measurement for comparison of preventive, rehabilitative, and curative treatments. This Mentored Research Scientist Development Award is proposed by the candidate to prepare him to help lead rehabilitation as it contributes to this integrative approach to the study of outcome in medicine. The proposed 5- year plan of course work, research seminars, and supervised research in health services, epidemiology, and health decision analysis is to provide the candidate with the necessary skills to function as an independent researcher in the area of rehabilitation and brain trauma cost and outcomes research. An experimental study of health-related quality of life, to be conducted within a recently NIH-funded randomized clinical trial, entitled "Magnesium Sulfate After Brain Trauma", is proposed. This randomized clinical trial of magnesium sulfate as a neuroprotectant after brain trauma will enlist 400 subjects and is collecting mortality, seizure frequency, and neurobehavioral data. The proposed study will conduct double-blind interviews with trial participants at 6 months post injury to obtain health-related quality of life data. Interviews will determine subjects' current health status using the EuroQol classification system (EQ-SD). Subjects will then value their current health using three well validated techniques: The Standard Gamble, Time Tradeoff, and Visual Analogue Scale. The primary hypothesis is that magnesium sulfate, given within 8 hours of moderate or severe head injury, improves subject valuation of their current health at 6 months post-injury. The study will also evaluate the cognitive burden associated with each method of valuation by testing each subject's consistency in placing values on their current health. Consistent subjects will judge additional hypothetical health states to construct a surrogate weighting scheme for use with subjects for which valuation is of too great a cognitive burden. Finally, the candidate plans to use data collected from the clinical trial on injury severity and cognitive impairment to both study the relationship between cognitive impairment and health-related quality of life judgments, and to develop ways to predict when injury severity will interfere with these judgments.